This invention relates generally to agricultural balers of the type commonly referred to as square balers that produce bales having a rectangular cross section, and more particularly to an apparatus for consistently controlling the length of bales produced by small square balers.
Square balers are implements that pick up a swath or windrow of crop material, such as straw or hay, from the ground and deposit it in an infeed housing where it is conveyed by a feed mechanism through an inlet to a bale forming chamber. Four walls define the bale forming chamber where the crop material is urged rearwardly by a reciprocating plunger to form a rectangular package of compacted crop material. The package so formed is automatically tied by a tying mechanism to complete the bale that is then discharged from the chamber by being urged rearwardly by the next bale being successively formed. Completed bales are either deposited on the ground for subsequent retrieval or they are delivered by appropriate means to a trailing wagon hitched to the back of the baler.
Pressure for increased efficiency in agricultural operations has led to increased usage of labor saving machinery to receive completed bales from the baler. Bale accumulator systems are one such machine commonly used in connection with small square bales. Use of such equipment has increased the demand on the baler to provide greater consistency in bale length so that the bale handling equipment will operate efficiently.
As crop is fed into a baler, each plunger stroke creates what is referred to as a wad or slice. The thickness and density of each slice is directly influenced by the amount of crop material delivered to the plunger for each stroke and the resistance applied to the bale being formed in the chamber behind the plunger. Resistance applied to the bale in the chamber is commonly controlled by variations in the size of the cross section of the chamber through which the crop material is being urged by the plunger by adjusting the position of one or more of the chamber side walls to vary the orifice through which the crop material is extruded. To this end, moveable tension rails, which define a portion of one or more of the walls of the chamber, are used to change the dimensions, i.e., the height and/or the width, of the chamber into which the crop material is being urged. Movement of the tension rails is accomplished by spring or hydraulic means.
Typically only the position of a pair of opposing bale chamber walls is varied in order to alter the bale chamber cross-sectional area. A linkage interconnects the walls so that a single actuator can control movement of the bale chamber walls. Balers having provisions for moving all four bale chamber walls generally incorporate a more complex linkage that enables a single actuator to reposition all four walls simultaneously or are otherwise configured to coordinate simultaneous movement of all four bale chamber walls. The result in many cases is that unequal pressure is exerted on the sides of the bale which results in inconsistent bale length and density.
It would be a great advantage to provide an improved bale chamber tensioning mechanism that would allow independent movement of opposing side walls of a bale chamber thus enabling uniform pressure to be applied to all four side planes of the bale being formed in the chamber thereby overcoming the above problems and disadvantages.